Lessons from York III

MY round-four game reached the following position after 18 moves.

White has just played 18.Qd1-f3!? in Richard Cowan (1972) - Spanton (1936)

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The game continued 18...a5 19.Rab1 Rad8 20.g5 Nh5 with equal chances.

What I wanted to play was the positional pawn sacrifice 18...e4!?

However I was worried that after 19.dxe4 Ne5 20.Qg3 Black did not have enough compensation.

In fact Stockfish17 and Dragon1 reckon Black is at least equal, and may have a slight edge.

They also reckon that an improvement is 19...d3 20.Ne3 (20.Qxd3? Bxf2+) Bd4!? 21.Bxd4 Nxd4, with at least the upper hand for Black.

In turn the engines give 19.Qe2!? as a possible improvement for White, although again they prefer Black.

Two things stand out: 1) 18...e4!? is probably a sound pawn sac; 2) I came nowhere close to unravelling what was possible in the position.

LESSON: when a move like 18...e4!? seems to be crying out to be played, it is usually wise to spend the time needed to thoroughly investigate the position.